Over the past 20 years, major progress has been made in our understanding of the epidemiology and consequences of ocular disorders among older adults. A number of population-based studies in a variety of major ethnic groups in the United States have provided critical information for etiological research and planning for delivery of eye care services to this high risk population. The situation among children is much different. While extensive data exist on the visual status of the school age population through legislatively mandated vision testing programs in elementary schools, few such data exist in the United States regarding the frequency and severity of ocular disorders among preschool age children. We propose to address this lack of information by conducing a population-based prevalence survey of ocular disorders among children 6 months through 5 years in the communities of Northeast and Southeast Baltimore. Over 39,000 households in 31 census tracts will be screened in order to identify approximately 6800 eligible children. Assuming an 80% response to the examination, this will yield over 5,000 subjects for study. All families who agree to participate will receive an enrollment interview conducted by telephone or at their home. Children will then be transported to an examination facility set-up in their local community where a detailed eye examination will be conducted. The examination will include measurement of visual acuity, refraction, ocular motility and alignment. Subjects in whom abnormalities are discovered will be referred to their preferred source of pediatric eye care for clinical management. A subset of children diagnosed with ocular disorders will receive a confirming examination by a pediatric ophthalmologist at the Wilmer Institute of Johns Hopkins School of Medicine. The analysis will focus on estimating the age and race-specific prevalence of ocular disorders in this group and on assessing the association of selected risk factors with the prevalence of these disorders.